Hey there!
Based on your question, your answer should be "y = d + 6", where y is the total amount of animals, d is the amount of dogs, and 6 is the number of cats. If you've been given the total amount of animals, you'll replace y with that number. 6 should remain constant since your problem states that there's 6 cats.
Your answer will be y = d + 6.
Hope this helped you out! :-)
